Electrical relay



Nov. 3, 1942; R. M. LAURENSON ELECTRICAL RELAY Filed Sept. 7, 1940 4 Sheets-Sheet l INVENTOR Hubert M.

AT'ToRNEY HIS Nov. 3, 1942.

R. M. LAURENSON ELECTRICAL RELAY Filed Sept '7, 1940 4 Sheets-Sheet 2 INVENTOR Robert M aurenson H15 A'ITTORNEY Nov. 3, 1942.

R. M. LAURENSQN ELECTRICAL RELAY.

Filed se i. 7, 1940 4 Sheets-Sheet 3 Insuliztion 7 hlll' INVENTOR aw enson HIS A-h-QRNEY Patented Nov. 3, 1942 UNITED STATES PATENT OFFICE ELECTRICAL RELAY Robert M. Laurenson, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissval'e, Pa, a corporation of Pennsylvania Application September '7, 1940, Serial No. 355,793

6 Claims.

My invention relates to electrical relays, and particularly to electrical relays which are suitable for use in railway signaling systems employing for the control of signaling devices direct current which is periodically interrupted or coded at different frequencies in accordance with traffic conditions.

More particularly, my present invention relates to relays for periodically interrupting or coding at a relatively low frequency, such, for example, as '75 cycles per minute, the direct current employed in systems of the type described, and one object of my invention is to provide a code transmitting relay which will maintain the desired code speed over a wide range of temperatures and impressed voltages.

Another object of my invention is to provide a code transmitting relay which is both economical to manufacture and operate.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

According to my invention, I employ a compound pendulum supported on a knife edge bearing and oscillated by an electromagnet the energization of which is controlled by a contact operated by the pendulum. The pendulum is operatively connected, in addition to the contact ior controlling the energization of the electromagnet, with a plurality of other contacts mounted on a top plate, which top plate and contacts are standard for a number of different relays, as described and claimed in the copending application for Letters Patent of the United States, Serial No. 304,811, filed on November 16, 1939, for Electrical relays.

I shall describe one form of electrical relay embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2 are side elevational views showing one form of relay embodying my invention, the two views being taken at right angles to each other, and certain of the parts being broken away or sectioned to better illustrate the construction of the remaining parts. Fig. 3 is a detail sectional view of a portion of the relay shown in Fig. 1. Fig. 4 is a vertical sectional view taken substantially on the line IV-IV of Fig. 2. Fig. 5 is a wiring diagram for the relay shown in the preceding views.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawings, the operating parts of the relay are all enclosed within a suitable case consisting of a transparent glass cylinderZ vided in the base plate.

clamped between a top plate I of moulded insulating material and a base plate 3, by means of long bolts 4 passing through clearance holes in the top plate and screwed into tapped holes pro- A gasket 5 of cork or other suitable material is interposed between the top plate I and the upper end of the glass cylinder 2, and a similar gasket 6 is interposed between the base plate 3 and the lower end of the cylinder, thereby sealing the case against the entry of dirt or other foreign substances.

A contact carrying rocker I of suitable insulating material is suspended from the top plate I for swinging movement between two extreme positions by means of two flexible strips 8 and 9 (see Figs. 1 and 3), and this rocker is provided with a plurality of flexible contact fingers l0 and H, each of which cooperates with a fixed contact member Illa or i la to close a contact l0llla or |llla. according as the rocker is swung to one or the other of its extreme positions. The contact fingers I0 and II are disposed in pairs and are secured to the opposite sides of the rocker within vertical grooves which maintain the fingers in the desired vertical positions, by means of studs l2 moulded into the rocker and provided at each end with a nut 13. The two studs l2 which secure the two end pairs of fingers l0 and H to the rocker also serve to secure the lower ends of the strips 8 and 9 to the rocker, and disposed between each strip 8 and 9 and the adjacent finger I0 is a spacing block 14 of such thickness that the lower ends of the strips 8 and 9 are disposed substantially at the center of the rocker. The upper ends of the strips are secured by means of rivets l5 and clamping blocks I6 to the heads of two spaced ter rninal posts I! which are mounted on the top plate I along with a plurality of other similar terminal posts; It will be seen therefore that the strips 8 and 9' not only serve to support the rocker, but also serve to electrically connect the two outer pairs of fingers with the associated terminal posts. The remaining two pairs of fingers are electrically connected with the vertically aligned terminal posts I! by means of flexible connectors I3. The positions of the flexible fingers when the fingers are out of engagement with the associated fixed contact member are determined by stops l9 which are clamped against the outer faces of the fingers by means of the associated studs [2, and which are so adjusted by bending them that the fingers will break the contacts in the desired positions in response to swinging movement of the contact carrying rocks! 1;.

When the relay is in operation, the rocker is oscillated between its two extreme positions at a relatively rapid rate, and in order to prevent breakage of the strips 8 and 9 due to the resultant flexing of the strips, the lower edges of the clamping blocks I6 on the sides next to the strips and the opposite lower edges of the heads of the associated terminal posts I! are rounded, as shown in the drawings, in such manner that any flexing of the strips which occurs adjacent these parts will be in the form of a gradual curve. Furthermore, the upper edges of the spacing blocks M on the side next to the strips and the opposite edges of the tops of the slots in the rocker are likewise rounded to prevent sharp bends in the strips adjacent these parts.

The fixed contact members Mia and Ila are similar to the fixed contact members Ian and lflb described and claimed in the Blosser application, Serial No. 304,811, referred to hereinbefore, and are adjustably secured to the lower ends of terminal posts 2| mounted on the top plate I on opposite sides of the terminal posts IT, in a manner which is also described in the said Blosser application. It is believed to be unnecessary, therefore, to describe the construction and arrangement of these fixed contact members any further herein.

The portion of the relay thus far described is well known, and is standard for a number of different types of relays, as has been pointed out hereinbefore.

The relay also comprises motor means embodying my present invention for oscillating the rocker between its two extreme positions to alternately operate the contacts at a constant relatively low preselected frequency. As here shown, this motor means consists of an electromagnet C having pole pieces 30a and 3622 secured by means of studs 3| to the plate portions 22a and 22b of a frame 22 in parallel spaced relation and connected together at one end by a core 30 surrounded by a winding 33.

The frame 22 is suspended from the top plate I, and has its main or upper part formed from a single piece of material bent generally into an inverted U-shape. The plate portions 22a and 22?) are of substantially trapezoidal form and terminate at their upper ends in spaced parallel arms 220 which form openings 22d through T which certain portions of the contact mechanism of the relay can be viewed for inspection. At their lower ends the plate portions 22a and 22b are clamped together by means of studs 23 passing through clearance holes in the plate portions and screwed into tapped holes provided in the opposite ends of spacing rods 24. It will be seen, therefore, that the frame provides a rigid support for the electromagnet C.

To facilitate changing the winding 33 to enable the relay to operate at the desired voltages, holes 25 having considerably larger diameters than the core 30 are formed in the plate portions 22a and 22b in axial alignment with the opposite ends of the core.

The pole pieces 30a and 30b cooperate at their lower or free ends with a magnetizable armature 35 which is secured within a rectangular groove 36 formed in the lower end of a compound pendulum P.

The compound pendulum P may have any suitable form possessing within the limited space available the necessary mass to cause it to have a. natural period equal to the desired code frequency, which may, for example, be '75 cycles 75 per minute. In the form here illustrated, this pendulum comprises a casting consisting of a central horizontal portion 31 provided at its opposite ends with upstanding arms 37a terminating at their upper ends in enlarged portions 31b, and with a central depending leg 73c terminating at its lower end in a foot 37d having the groove 36 referred to hereinbefore formed therein.

Secured by machine screws 38 against a machined surface 31e formed on one side of the horizontal portion 3'! of the pendulum P centrally thereof is a rectangular metal plate 39, the lower edge of which is provided with an inverted V-shaped groove 39a. The apex of this groove is located at the point about which it is desired to have the pendulum oscillate, and this groove receives a knife edge formed on a knife edge member 49. The knife edge member 18 is secured by means of machine screws 4| to one side of a supporting member 42 which member, in turn, is secured at its ends to the plate portions 22a and 22b of the bracket 22 by means of studs 43. The metal plate 39 and knife edge together form a knife edge bearing, and these parts are constructed of a special hardened steel to insure long life with a minimum amount 0! friction and wear.

Also formed on the horizontal portion .i'l of the pendulum P at its opposite ends are two laterally projecting lugs 31f (see Fig. 2), each of which is provided with an opening 379 extending therethrough. The openings 31g align axially with the axis of rotation of the pendulum P, and have pressed or otherwise secured therein end thrust pins 3171. provided with enlarged heads 372' disposed in the enlarged outer ends of the holes. These heads cooperate with the inner ends of screws 44 which are adjustably screwed through the plate portions 22a and 22b of the bracket 22 and carry lock nuts 45 and lock washers 46 for securing them in their adjusted position. The screws 44 and pins 31h together constitute a means for limiting endwise movement of the pendulum, and serve to keep the knife edge bearing members in the proper relative vertically aligned longitudinal positions. The portions of the screws which extend into the enlarged outer ends of the openings 31h are somewhat smaller in diameter than the enlarged outer ends of the openings 31g to prevent frictional contact between the screws and the pendulum. The end surfaces of the screws and the heads 312' of the pins are both chromium plated and polished to reduce friction and to insure long life with a minimim amount of wear.

The enlarged portions 31b on the upper ends of the arms 31a of the pendulum have their opposite sides flattened and are provided with tapped holes 317' for the reception of machine screws 41, whereby removable weights id may attached to the pendulum to obtain frequency adjustment. Adjustment is made at the upper end of the pendulum since smaller adjusting weights are required for a given frequency change than would be required at the bottom of the pendulum. The weights 48 may taken any convenient form, the particular form shown consisting of metal strips of different thicknesses. These weights also provide a means for causing the pendulum to stop in the desired position when the relay is deenergized.

The pendulum P is operatively connected with the rocker I through the medium of an arm 58, the upper end of which is secured to the center of the rocker 1 within a vertical groove by means of a bolt 49, as best seen in Fig. 4. The lower end of the arm is provided with bifurcations 58a which straddle the upper end of the metal plate 39 and cooperate with driving buttons 50 secured to the plate 39. The driving buttons are rounded, and the parts are so proportioned that oscillation of the pendulum P will cause these buttons to engage one or the other or both of the bifurcations in a point to point contact without binding in all positions of the pendulum. To prevent Wear the buttons and cooperating faces of the bifurcations are preferably chromium plated and polished.

With the pendulum operatively connected with iii the rocker in the manner just described it will be apparent that rotation of the pendulum in one direction will cause swinging movement of the rocker in the opposite direction, and the parts are further so proportioned that oscillation of the pendulum through its normal amplitude will cause movement of the rocker between its two extreme positions.

The length of the armature 35 is such that it is free to swing between the pole pieces 33a and 33b", and it will be seen, therefore, that energization of the winding 33 will tend to pull the armature between the pole pieces and hence will swing the rocker 1 in a clockwise direction as viewed in Fig. 4. The supply of energy to the winding 33 is controlled by two driving contacts comprising two contact fingers 5| and 52 (see Fig. 4) which operate with fixed contact members 5la and 52a respectively. The fingers 5| and 52 are secured to the opposite sides of the rocker l by means of the bolt 49 which secures the arm 58 to the rocker. This bolt also serves to electrically connect the two fingers 5| and 52 together. The fixed contact members 5 la. and 52a are similar to the fixed contact members Illa and Ila and are adjustably secured to supporting posts 55 and 51 in the same manner as the fingers Ma and Ila. A top 53 is associated with the finger 5| to position it when it is out of engagement with the associated fixed contact member 5la, but no stop is provided for the finger 52 since the arm 58 performs this function. In order to permit the low resistance contact button on the finger 52 to engage the fixed contact member 52a, a hole 55 (see Fig. 3) is formed in the arm 58, which hole receives the contact button with considerable clearance. The fixed contact members are so adjusted that when the rocker occupies its normal position to which it is biased by the pendulum P, both contacts 5l5la and 5252a will be closed, but that when the pendulum moves a small distance in a counterclockwise direction, as viewed in Fig. 4, the contact 5252a will open, and that when the armature moves a small distance in the opposite direction the contact 5l--5la will open.

Referring now to the wiring diagram illustrated in Fig. 5, it will be seen that the one terminal of the winding 33 is connected by a wire 33a with the post 55 which is connected with the fixed contact member 5Ia, and the other terminal is connected by a wire 3312 with the post 59 which is connected with the contact member 52a. A source of electromotive force here shown as a battery B is connected between a supporting post 51 and the post 59 through a switch S. It follows, therefore, that when the switch S is closed winding 33 will be supplied with current provided contacts 5I-5la. and 52-52a.- are then both closed, but the supply of current will be interrupted When either contact 5l-5la or 52-52a becomes opened. In order to prevent excessive arcing of the contacts iii-51a and 52-52a, a rectifier R is connected in multiple with the winding 33. The rectifier is supported at its ends in slots 68 provided in the plate portions 22a and 22b of the frame 22, as shown in Fig. 1.

As shown in the drawings, the switch S is open so that the winding 33 is deenergizecl. Rocker I therefore occupies its normal position to which it is biased by the pendulum P, and under these conditions the contacts l0l0a and H-l la are all open and 5l5la and 52--52a are all closed. I will now assume that switch S becomes closed. Since contacts 5I-5la and 5252a are both closed current from battery B is supplied to winding 33, and flux lines are therefore set up in the air gap between the pole pieces 30a and 3%. These flux lines thread the armature 35, and as will be readily understood, exert a force on the armature which rotates it and the pendulum P i in a counterclockwise direction, as viewed in Fig.

i. This rotation, in turn, rotates the rocker 1 in a clockwise direction as viewed in Fig. l, and the contact 5252a is so adjusted that when the pendulum has swung to the position in which the armature 35 is between the lower ends of the pole pieces 38a and 3%, this contact will open and will deenergize winding 33. The pendulum P, however, will continue to swing in the direction it was previously moving until the kinetic energy which it has acquired is expended in stressing the contact fingers I3 and in bending the flexible strips 8 and 9 which support the rocker. When this happens, the energy stored in the contact fingers H3 and in the flexible strips, and in armature 35 due to its position, will reverse the direction of rotation of the rocker 1, so that it will now rotate in a counterclockwise direction. During this latter rotation contact 5252a will again become closed. Due, however, to the construction of winding 33, the field between the pole pieces 39a and 36b will build up slowly, and since the pendulum is now rotating in a clockwise direction, as viewed in Fig. 4, by the time the field has built up between the pole pieces to its normal value, the pendulum together with the armature 35 will have swung to the position where the electromagnet will have little effect on the armature. As soon as the armature moves a small distance in a clockwise direction from its normal position, as viewed in Fig. 1, contact 5 i-5 in will open and will deenergize winding 33. It will be seen, therefore, that winding 33 will be deenergized as soon as the pendulum moves a small distance in either direction from its neutral or gravity biased position. When the armature reaches its extreme clockwise position, as viewed in Fig. l, the energy stored in the contact fingers ii, the flexible strips 8 and 9 and the pendulum will cause the rocker I to again rotate in a clockwise direction. As soon as the rocker reaches the position in which contact 5i5la closes, electromagnet C will again cause a force to be exerted on the pendulum carried armature tending to accelerate the pendulum. The parts are so proportioned that the energy supplied to the pendulum during this counterclockwise rotation is greater than that expanded in overcoming friction and other losses during this counterclockwise rotation and the previous clockwise rotation together with that expended in overcoming the opposing force of the magnet pull on the 'arma ture during the previous clockwise rotation, so that the pendulum starts to oscillate at a period which depends upon its mass. This can be varied in the manner previously described to provide any desired code speed within the limits of the apparatus.

It will be apparent that the oscillation of the pendulum will cause the contacts lllla and I I--Ha to be alternately opened and closed at the frequency of oscillation of the pendulum. These contacts may be used for coding purposes, as will be readily understood.

It should be pointed out that the double break arrangement provided for the energizing circuit for the winding 33 by the contacts 5l5la and 52--52a reduces energy requirements to a minimum, and tends to keep the energy in the energizing winding 33 fairly constant for wide variations of applied voltages, and in consequence thereof tends to keep a constant code speed for voltage ranges such as may be expected in battery circuits.

As will be apparent from an inspection of the drawings the pendulum P possesses considerable mass, and unless some means are provided to prevent it from swinging during handling of the relay, damage is likely to result to the knife edge hearing, or to other parts of the relay. In accordance with my present invention, I prevent the pendulum from swinging during handling by means of two screws 60 and BI which are screwed through threaded holes 62 and 63 provided in the base plate 3. These screws are provided with pointed ends and are so positioned that if they are screwed inwardly when the pendulum occupies its gravity biased position the pointed ends of the screws will enter conical holes 54 in the underside of the armature 35 and will lift the pendulum vertically to the position in which the inner ends of the screws 44 move into engagement with the bottom sides of the enlarged portions of the openings 31g in the lugs 31f. In this position of the armature, it is locked against movement, and the two bearing members are separated from each other, and it will be seen therefore that all parts of the relay will then be protected from damage which might result if the pendulum were free to move. in this holding position by means of look nuts 65 screwed onto the lower ends of the screws.

When the pendulum has been locked in place for shipment and it is subsequently desired to put the relay in service, the shipping screws EB and 6| are removed and the holes in the base plate are filled with suitable plugs which may for example comprise short screws.

One advantage of holding means embodying my invention is that it provides a simple and effective method for protecting the relay parts during shipment.

Although I have herein shown and described only one form of electrical relay embodyingmy invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. An electrical relay comprising a contact carrying rocker mounted for swinging movement between two extreme positions, a pendulum, a plate member secured to said pendulum and comprising part of a knife edge bearing for pivotally supporting said pendulum for oscillation at its natural period, means for operatively connecting said rocker with said pendulum comprising a rigid arm secured at one end to said The screws are arranged to be locked rocker and provided at the other end with bifurcations which straddle said plate member, and motor means for oscillating said pendulum at substantially its natural period to cause said rocker to oscillate at a constant preselected frequenoy.

2. An electrical relay comprising a contact carrying rocker mounted for swinging movement between two extreme positions, a pendulum, a plate member secured to said pendulum in a vertical position and provided in its lower edge with a V-shaped notch the apex of which is disposed at the axis about which said pendulum is intended to oscillate, a fixed knife edge hearing member the knife edge of which engages said plate member at the apex of said notch, whereby said pendulum is pivotally supported for swinging movement at substantially its natural period, a rigid arm secured at its upper end to said rocker and provided at its lower end with bifurcations which straddle the upper part of said plate member, rounded driving buttons secured to said plate member and cooperating with said bifurcations in such manner that said buttons will engage one or the other or both of said bifurcations without binding in all positions of said pendulum to cause said rocker to oscillate in response to oscillation of said pendulum, and motor means for oscillating said pendulum.

3. An electrical relay comprising a contact carrying rocker mounted for swinging movement between two extreme positions, a pendulum, a plate member secured to said pendulum and comprising part of a knife edge bearing for pivotally supporting said pendulum for oscillation at its natural period, means for operatively connecting said rocker with said pendulum comprising a rigid arm secured at one end to said rocker and provided atthe other end with bifurcations which straddle said plate member, an armature carried by and forming a part of said pendulum, an electromagnet cooperating with said armature and effective when energized to exert a force on said armature which tends to move said pendulum away from its gravity biased position, and contacts carried by said rocker for controlling the energization of said electromagnet, the parts being so proportioned that when said electromagnet is energized over said contacts said pendulum will oscillate at substantially its natural period.

4. An electrical relay comprising an insulating top plate, a contact carrying rocker suspended from said top plate for swinging movement between two contact operating positions, a frame secured to the underside of said top plate and provided with spaced vertically disposed plate portions, a pendulum supported between said plate portions by means of a knife edge bearing including a vertically disposed bearing member secured to the pendulum, lugs formed on said pendulum on opposite sides of said bearing provided with openings which align axially with the knife edge of said bearing, adjusting screws screwed through said plate members in axial alignment with said openings and extending at their inner ends into said openings, pins secured within said openings and provided with rounded portions which cooperate with the inner ends of said screws to prevent endwise movement of said pendulum, means secured to said rocker and cooperating with said bearing member for operatively connecting said rocker with said pendulum,

and motor means for at times causing said pendulum to oscillate.

5. An electrical relay comprising a pendulum pivotally supported by means of a knife edge bearing, openings provided in said pendulum on opposite sides of said bearing in axial alignment with the axis about which said pendulum oscillates, end thrust pins provided with rounded heads disposed in the enlarged outer ends of said openings, screws adjustably mounted in axial alignment with said openings in fixed supports and extending into the enlarged outer ends of said openings with clearance and cooperating with the heads of said pins to limit the movement of said pendulum along its axis of oscillation, means for oscillating said pendulum at substantially its natural period, and means for at times securing said pendulum in a fixed position including screws efiective when screwed to one position to cause said first mentioned screws to engage said pendulum at said openings, the parts being so proportioned that when said first mentioned screws are engaging said openings the knife edge of said bearing will be out of contact with the remainder of the bearing.

6. An electrical relay comprising a compound pendulum having a central horizontal portion provided at its ends with upstanding arms terminating in enlarged portions and intermediate its ends with a depending leg terminating in a foot, said central portion also being provided with laterally extending laterally spaced lugs, a bearing member secured to said central horizontal portion between said lugs in a vertical position and provided in its lower edge with a V-shaped notch the apex of which coincides with the axis about which said pendulum is intended to oscillate and with the axes of aligned openings provided in said lugs, a fixed knife edge member the knife edge of which cooperates with said bearing member at said notch to form a knife edge bearing, pins having rounded heads disposed in the enlarged outer ends of said openings, screws adjustably mounted in fixed supports in axial alignment with said openings and extending with clearance into the enlarged outer ends of said openings and cooperating with the rounded heads of said pins to maintain said pen-- dulum in the proper longitudinal position with respect to its axis of rotation, adjustable weights secured to the enlarged portions of said arms for adjusting the period of said pendulum and the position to which it is biased by gravity, an armature secured to the foot portion of said pendulum, and motor means cooperating with said armature to cause said pendulum to oscillate substantially at its natural period.

ROBERT M. LAURENSON. 

